{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T23:25:56Z","timestamp":1792797956806,"version":"4.5.0"},"reference-count":36,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2022,10,6]],"date-time":"2022-10-06T00:00:00Z","timestamp":1665014400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Medicina"],"abstract":"<jats:p>Background: The hyperventilation test is used in clinical practice for diagnosis and therapeutic purposes; however, in the absence of a standardized protocol, the procedure varies significantly, predisposing tested subjects to risks such as cerebral hypoxia and ischemia. Near-infrared spectroscopy (NIRS), a noninvasive technique performed for cerebral oximetry monitoring, was used in the present study to identify the minimum decrease in the end-tidal CO2 (ETCO2) during hyperventilation necessary to induce changes on NIRS. Materials and Methods: We recruited 46 volunteers with no preexisting medical conditions. Each subject was asked to breathe at a baseline rate (8\u201314 breaths\/min) for 2 min and then to hyperventilate at a double respiratory rate for the next 4 min. The parameters recorded during the procedure were the regional cerebral oxyhemoglobin and deoxyhemoglobin concentrations via NIRS, ETCO2, and the respiratory rate. Results: During hyperventilation, ETCO2 values dropped (31.4 \u00b1 12.2%) vs. baseline in all subjects. Changes in cerebral oximetry were observed only in those subjects (n = 30) who registered a decrease (%) in ETCO2 of 37.58 \u00b1 10.34%, but not in the subjects (n = 16) for which the decrease in ETCO2 was 20.31 \u00b1 5.6%. According to AUC-ROC analysis, a cutoff value of ETCO2 decrease &gt;26% was found to predict changes in oximetry (AUC-ROC = 0.93, p &lt; 0.0001). Seven subjects reported symptoms, such as dizziness, vertigo, and numbness, throughout the procedure. Conclusions: The rise in the respiratory rate alone cannot effectively predict the occurrence of a cerebral vasoconstrictor response induced by hyperventilation, and synchronous ETCO2 and cerebral oximetry monitoring could be used to validate this clinical test. NIRS seems to be a useful tool in predicting vasoconstriction following hyperventilation.<\/jats:p>","DOI":"10.3390\/medicina58101396","type":"journal-article","created":{"date-parts":[[2022,10,9]],"date-time":"2022-10-09T04:00:02Z","timestamp":1665288002000},"page":"1396","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Near-Infrared Spectroscopy Usefulness in Validation of Hyperventilation Test"],"prefix":"10.3390","volume":"58","author":[{"given":"Stefan","family":"Sandru","sequence":"first","affiliation":[{"name":"Department of Functional Sciences, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dan","family":"Buzescu","sequence":"additional","affiliation":[{"name":"Department of Functional Sciences, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carmen Denise Mihaela","family":"Zahiu","sequence":"additional","affiliation":[{"name":"Department of Functional Sciences, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ana","family":"Spataru","sequence":"additional","affiliation":[{"name":"Department of Critical Care, King\u2019s College Hospital Denmark Hill, London SE5 9RS, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9213-6735","authenticated-orcid":false,"given":"Anca Maria","family":"Panaitescu","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology, Filantropia Clinical Hospital Bucharest, 011171 Bucharest, Romania"},{"name":"Department of Obstetrics and Gynecology, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2687-2611","authenticated-orcid":false,"given":"Sebastian","family":"Isac","sequence":"additional","affiliation":[{"name":"Department of Functional Sciences, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cosmin Ion","family":"Balan","sequence":"additional","affiliation":[{"name":"Department I of Cardiovascular Anesthesiology and Intensive Care, \u201cProf. C. C Iliescu\u201d Emergency Institute for Cardiovascular Diseases, 050474 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4302-629X","authenticated-orcid":false,"given":"Ana-Maria","family":"Zagrean","sequence":"additional","affiliation":[{"name":"Department of Functional Sciences, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bogdan","family":"Pavel","sequence":"additional","affiliation":[{"name":"Department of Functional Sciences, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,10,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"557","DOI":"10.1016\/0002-8703(45)90212-2","article-title":"Studies concerning the etiology and pathogenesis of neurocirculatory asthenia: IV. 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